While heat development, for example, of an economical power-optimized diesel engine on the engine block can be very low, this situation in no way applies to “hot zones” as in the manifolds, turbochargers, catalytic converters, etc. Due to the increasingly compact configuration of engines, components which are not thermally “compatible” are increasingly ending up in close proximity. Accordingly, it is necessary, using so-called shielding parts, such as heat shields, to protect thermal engine components facing adjacent heat-sensitive assemblies, such as sensors, fuel lines, pressurized sensors, body parts, etc. The situation is also exacerbated by the compact structure in that the high packing density of the assemblies constricts the cooling air flow in the engine compartment. Noise abatement measures may also contribute to this problem. Thus, for example, plastic bottom plates which are designed to reduce the emergence of noise from the engine compartment onto the roadway under certain circumstances can produce effective insulation with which heat is contained in the engine compartment. Catalytic converters, due to their phased high surface temperature, are considered heat sources which certainly necessitate the use of protective shield barriers. One typical example involves design-engineering measures, such as positioning of the catalytic converter tightly on the manifold of the overall exhaust system. This design principle, which is used for rapid heat-up of the catalytic converter to reduce emissions in the cold starting phase, shifts a strong heat source into the engine compartment where numerous assemblies are crowded in a narrow space. Likewise, one cause of the growing importance of shielding parts such as heat shields is the tendency towards use of thermoplastics. The outstandingly moldable, light and economical materials are becoming noticeably more common in the engine compartment, but require special attention with respect to the ambient temperatures at the application site, relative to the other thermal engine parts (New Materials and Development Tools for Heat Protection, in MTZ December 2001, Volume 62, page 1044 ff.).
DE 102 47 641 B3 discloses a structural component, especially in the form of a noise-damping shielding part as a component of the motor vehicle. To improve noise abatement in the known structural component, the pertinent shielding part includes a shielding body with a base edge as a structural part of the first type. It may be mounted on the edge side by angular clamp legs within the engine compartment on the stationary parts there, and shields thermal engine components facing heat-sensitive components.
The shielding body as a structural part of the first type is arched in a U-shape in the middle area, and is configured to be symmetrical in this respect. This middle area is arched in a U-shape on the edge side into the edge areas, and undergoes transition into greater curvature. On the two opposing edge areas, the angular clamps are mounted subsequently as fastening means. The shielding body has two layers of sheet metal, between which a noise-damping and/or heat insulating insulation layer extends. To fasten the cover layers of sheet metal to one another, flanging is used in which the free flared flange of one cover layer superficially encloses the edge area of the other cover layer. To reduce weight, the shielding body is made of aluminum or some other lightweight metal.
The known solution is used preferably for shielding a coupling between the transmission flange and a universal shaft against structure-borne noise originating from the transmission as well as the continuous influence of the temperature radiation of the adjacently extending exhaust pipe. During tests, a reduction of noise emission by 3 dB was achieved in the known solution. In order to achieve the pertinent shielding action, other structural parts of a second type extending in the form of bead-shaped lengthwise, and transverse ribs over the convex outer side of the shielding body extend along the middle area of the first structural part in the form of a shielding body. It is characteristic in this known structuring that the lengthwise ribs extending over the entire length of the shielding body are adjoined by transverse ribs molded on in one piece. The transverse ribs form a type of nub structure, and fit adjacently between two respective transverse ribs of an adjacent lengthwise rib in an alternating sequence at intermediate distances. The edge areas which are curved more dramatically to the outside with the connecting clamps are conversely kept free of the aforementioned ribs. With respect to the interrupted transverse rib structure of the known solution, it is to be expected that stiffness and strength are reduced in this respect. Furthermore, at the transition site to the connecting clamps, stiffening of the shielding body is acquired only by the bent clamp legs which largely define the connection geometry, here of the structural component on the stationary engine components or chassis components. This arrangement limits the possible applications of the known structural part accordingly. The connecting clamps with their bent clamp legs and eye connecting points for penetration of a fastener (screw) on the one hand require installation space and on the other they increase the weight for the known solution. Also, the known solution is unsuitable for thermal insulation of larger areas in the engine compartment.